Opposition Leader Malcolm Turnbull says he has the support of Joe Hockey to stay on as leader.

Opponents of Mr Turnbull and his position on climate change are spending the weekend trying to secure the numbers to make sure he is forced out of his job.

Senior Liberals are trying to convince Joe Hockey to challenge for the leadership at Tuesday's partyroom meeting.

But Mr Turnbull says Mr Hockey supports him as leader and is committed to passing the Government's amended emissions trading scheme (ETS).

"He certainly does, Joe Hockey has again and again and again endorsed the policy that I stand for, the Shadow Cabinet stands for," he said.

"Joe Hockey is on the record more times than you can mention."

Mr Turnbull says he is confident he has the support of his party to win a leadership vote.

But he says the Coalition must honour their commitment to passing an amended ETS.

"I can readily understand the Government's frustration - what does it say about the character of the Liberal Party if, having entered into an agreement, we were to simply say oh well, we've changed our minds, we're going to renege on that deal," he said.

"How could you trust us? We have to be a party of integrity and that means when you make a deal, when you reach an agreement, you stick to it."

Mr Hockey has previously said he will not challenge for the leadership. Earlier this week, he took to Twitter to ask for feedback on the emissions trading scheme and yesterday he went back to Sydney to talk to his family.

Liberal sources say once a spill motion is moved and is successful, then technically there is no leader, so if Mr Hockey stands then it will not be seen as a challenge.

The man who is challenging Mr Turnbull, Tony Abbott, may step back if Mr Hockey runs, because he says he is not interested in the leadership role at this point.

Dissidents speak out

The Federal Member for Indi, Sophie Mirabella, who quit the frontbench this week, has told Sky News Mr Turnbull will not survive Tuesday's leadership ballot.

"No, the position is untenable," she said.

Victorian Liberal Senator Mitch Fifield was one of the first to offer his resignation in a group of three parliamentary secretaries who resigned from the front bench earlier this week.

Senator Fifield is keeping quiet about whether his team has the numbers to unseat Malcolm Turnbull.

"I am not counting heads or anything of that nature. I am seeking to hand a resolution to the current impasse that we have at the moment," he told Lyndal Curtis on AM.

"I think Malcolm has impugned the motives of anyone who has issues with Labor's ETS [emissions trading scheme] legislation as opposed to his leadership, and I would have thought that opposing bad Labor legislation and supporting the Liberal Leader weren't mutually incompatible.

Senator Fifield says he does not think the party room will back Mr Turnbull on Tuesday.

In this term in Parliament, Liberal senators have twice defied their leader and Senator Fifield gives no guarantee that they will not rebel against a new leader.

"Liberal senators, like all colleagues, obey and observe the decisions of the party room on most occasions," he said.

"But what contrasts us from the Labor Party is that we jealously guard the right to exercise individual judgement and to express that on occasion in the Parliament."

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